IBM Support

FlashCopy Background Copy and Cleaning Rate Dependent on Mapping Grain Size in SVC -



When using SVC -, the data rates published for FlashCopy background copy and cleaning rate are incorrect for maps which use a non-default (64KB) grain size.


The following table provides the relationship of the FlashCopy background copy and cleaning rates to the user specified rate when using SVC -

User specified valueData copied/sec
with 256 KB grain size
Data copied/sec
with 64KB grain size
1-10128 KB32 KB
11-20256 KB64 KB
21-30512 KB128 KB
31-401 MB256 KB
41-502 MB512 KB
51-604 MB1 MB
61-708 MB2 MB
71-8016 MB4 MB
81-9032 MB8 MB
91-10064 MB16 MB

These values represent the rates which an SVC cluster tries to achieve in an optimal environment, where there are no performance constraints.

Resolving The Problem

This issue was resolved in the release of the SAN Volume Controller software, where a given user specified rate achieves the same data rate independent of the grain size used for the mapping.

Internal Use Only

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Wording Provider - Chris Canto
Related to VRM's - -, fixed in
Defects / work items - 112139 (to publish the technote)
First Review Date - 08/02/2010 - first publish
Last Review Date - 18/05/2010 - republished to state fixed in PTF
Reviewed By - Steve White, Chris Beeken
23/09/2010: EH/ GL reviewed. This document relates to SVC V5.1.x and earlier only.

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Document Information

Modified date:
17 June 2018